Most modern fly fishing reels are equipped with a directional clutch and brake arrangement (commonly referred to as a drag mechanism) which allows for free spinning of the reel when line is taken in an and adjustable level of resistance on the rotation of the reel when line is being let out. The purpose of the resistance, or “drag”, is to maintain a constant level of tension on the line once a fish is hooked without completely binding the reel which could result in a broken line.
The most common type of drag utilized in fly fishing reels is a draw bar type disc drag mechanism. Other types of mechanisms, such as gear drags or hydraulic drags are also well known.
In a draw bar type of drag mechanism, a substantially flat drag plate is coaxially mounted with respect to the rotating spool portion of the reel using a clutch mechanism which can be achieved in a number of ways: by way of incorporating a one-way clutch bearing in the drag assembly, a directional spring loaded ratchet mechanism (commonly referred to as a pawl mechanism), or any other mechanism that allows for rotation in a single direction whilst preventing rotation in the other direction. The drag plate is mounted so that its face abuts the rotating spool, or alternatively, a separate element that is mechanically affixed, or otherwise coupled, to the rotating spool. The face of the drag plate that interfaces with the rotating spool is lined with a friction-producing material. The drag plate is held in juxtaposition to the rotating spool by means of an adjusting mechanism. The adjusting mechanism enables the reel's operator to adjust the pressure with which the drag plate is held against the rotating spool or corresponding element.
In operation, the clutch mechanism permits the drag plate to rotate in conjunction with the rotating spool when line is being taken into the reel. When line is being let out of the reel, the one-way clutch holds the drag plate stationary in relation to the rotating spool. By holding the drag plate stationary, friction is created between the rotating spool and drag surface affixed or otherwise coupled to the drag plate. The friction acts as a drag against the rotating spool and (assuming the force with which the line is being taken out remains constant) slows its rate of rotation. By adjusting the pressure exerted by the drag plate against the rotating spool through the adjustment mechanism, the amount of friction between these elements can be varied and the drag can be thus optimized to the liking of the operator.
A common type of disk drag mechanism in fly fishing reels utilizes cork as the friction-producing material. Cork is good material for a drag plate lining due to the fact that it is compressible and this creates a smooth, constant drag pressure. Cork is also resistant to heat and water and is capable of producing a wide range of drag resistance with proper adjustment and lubrication.
Cork, however, has definite drawbacks. The most salient drawback is that cork requires periodic lubrication. An unlubricated cork drag will quickly break up under strenuous use. The need for lubrication prevents the use of cork in “sealed” drag mechanisms and adds the requirement of periodic maintenance. Another drawback of cork drags is that when wet they have a tendency to either “hydroplane”, and thus be completely ineffective, or vibrate (also known as “chatter.”) Finally, cork drags have relatively high breakaway friction, (also commonly misnomered as startup inertia within the fly fishing industry). That is, at the very beginning of engaging pressure on the line, before rotation of the spool has begun, as pressure is applied in increasing force on the drag, until that force exceeds the drag's static resistance (breakaway friction), and rotation begins, the drag resistance is slightly greater (or much greater, depending on the drag interface material) than it is during rotation (running friction). This means that in order to maintain a truly constant level of drag, an operator has to periodically increase and decrease the drag plate pressure to adjust for this differential in drag every time the spool comes to a full stop.
A popular alternative to cork is carbon fiber. Carbon fiber offers the advantages of being a self-lubricating drag material which permits its use in sealed mechanisms and eliminates the need for external lubrication or maintenance. Carbon fiber is also not negatively impacted by water in the same way cork is, hence its wide range of application from automobile brakes to fly fishing reels. Finally, carbon fiber offers virtually no breakaway friction (startup inertia) against a smooth breaking surface.
However, carbon fiber, like cork, has drawbacks in its application for fly fishing reels. The principal drawback is that carbon fiber is not nearly as efficient a thermal insulator as cork. In a cork disk drag mechanism, virtually all of the heat that is created at the interface of the drag plate lining and the rotating spool is dissipated into the rotating spool. This is so because cork is a thermal insulator which does not absorb heat and prevents any heat from conducting to, and building up on, the drag plate. Dissipation of heat into the rotating spool is desirable because it is a relatively large mass component which is able to absorb and dissipate the heat without any significant rise in temperature. Further, because the spool is rotating and thus exposed to significant air circulation, the heat is easily transferred out of the spool.
By contrast, in a carbon fiber disk drag mechanism, the carbon fiber lining is very thin and during prolonged periods of running friction, absorbs, retains and transfers heat very well. The heat, rather than being entirely dissipated by the rotating spool, is partially transferred to the drag plate. The amount of heat generated by a carbon fiber disk drag mechanism is surprisingly high. Temperatures often exceed 300° F. As a result of this, the drag plate, which is static, can become very hot. This heat is in turn transferred to other elements of the reel, namely the bearings supporting the rotation of the drag plate, and the one-way clutch (if present). This heat build up causes the lubricant in the bearings and one-way clutch to liquefy and leak out of the bearings, break down and eventually causes the bearings to fail. Thus, reels employing conventional carbon fiber disk drag mechanisms have a much lower reliability when compared to those using cork when large amounts of drag are required. This is why traditionally, offshore or big game fly fishing reels have mostly employed cork drags,
Another impact of the heat transfer to the drag plate is the resulting expansion of the drag plate (or drag plates if in a stacked drag assembly commonly used in fly fishing reels where the spool's interfacing surface is limited). This expansion, especially in a stacked drag assembly, causes the pressure, and accordingly the friction produced, between the drag plate(s) and the rotating spool to increase in direct proportion to the rotational rate of the spool. As the pressure increases so does friction and drag force. Therefore, with a carbon fiber disk drag mechanism the operator must adjust the drag downwards or risk too much drag being applied and the line breaking. Once the spool cools down, an upwards adjustment to the drag is needed as the pressure decreases due to the contraction of the cooling drag plate.
Accordingly, there is a need in the relevant field of art for a fly fishing reel with a drag mechanism that combines the advantages of cork and carbon fiber mechanisms. Specifically, there is a need for a fishing reel with a drag mechanism that is self-lubricating, has very low breakaway friction (start-up inertia), is heat and moisture resistant and provides smooth, constant drag pressure in most conditions without the need for repeated adjustment.